No matter for how long you play and in what manner, the landscape always stays the same. It needs some variety and so I make these small ideas that could make game more dynamic (in my opinion of course).

1. Day/Night Cycles

After playing 10 minutes of normal, typical game of Reus, the sun would hide turning beautiful day into cold, dark night. There would be new types of animals (Owls, Bats, Hedgehogs, etc.), more dangerous thus turning night into fight for survival. The plants would give less food and Giants would be much slower, especially on unilluminated paths. Our goal would be to help villagers to defend themselves from hungry predators. Night could also turn minerals into caves with different boosts: will you make a ice cave, giving a lot of wealth but also generating swarms of ravenous bats looking for plants or a small, flooded cave with few Natura bonuses and nothing more?

2. Seasons

4 seasons: Spring, Summer, Autumn, Winter... Each with different animals and plants, each with different type of weather.
On spring, the flowers start blooming and animals waking from winter sleep. There are much less fruits and minerals are harded to gather, as the snow hasn't thawed yet. Rain is a common thing, giving fertility boosts to all plants, additionaly healing damaged patches, villages and giants. If there would be day night cycle, both would last the same.
However, in the summer day is much longer. With the sun shining, the plants are giving fruits, minerals are the most effective and animals are active. Unfortunately, the massive heat is very dangerous, searing oceans and overheating people who are willing to go on war. Worse than swelter can be a storm, damaging villages and giants, so you need to be prepared and take care of your people! But do not worry, holidays are really good for making money. A lot of summer camps show up, bringing a lot of wealth, so make good use of it.
During the autumn, animals and plants are preparing to go to sleep; there are less and less fruits and animals are slowly hiding in their lairs. Days become shorter and night longer. The weather is quite depressive: creamy fog is slowling down your Giants, while hail is damaging the villages. However, it doesn't mean that Autumn hasn't got its advantages! In few days, people are gathering a lot of food which doesn't increase their Greed. Also, during this ugly weather nobody wants to fight, so you don't need to worry about wars.
Last season is cold, dark winter. Days here become very short, temperature is far below zero. The snow is falling, making people move slower but giving them new opportunites when oceans freeze up. Geysers and volcanoes are the best way to warm up, making people interested in them, giving a chance to make a skii resort, hot springs and more! The winter is the best for thinking, so you can expect huge amount of Tech points... and more people during these looooong, dark nights ;)

I think adding different animations for day and night is good, as well as for seasons, but if sources fluctuate through changes in time of day and climate, I think that would require an immense change in balance of the game. The developers already tried to experiment with a weather system. To my knowledge, it didn't work so well. As for winter, I'm still looking for that frost giant, but I guess it's a long way off. :p

I realise that adding seasons, day-night cycle or even weather must be carefully considered, planned as even the smallest thing can destroy balance of the game. Also, we'd need bigger planets and longer playtime to achieve anything in changing quickly seasons. Anyway, I believe this idea is worth considering :D

Sure the flashing red town looks scary, but what about a thunderstorm appears above the evil town and flashes lightning.

Watching seasons happen would be interesting too. I think you could implement seasons every 5 mins of the game your playing. Seasons would give +/- depending on location. Such as: winter in a forest would decrease food from plants and animals but would raise them with added tech. or summer in the desert adds more animal food and wealth. IDK, but balance has to definitly be tested with all of these things first.